This invention relates to an improved vibration grip for impact tools such as nail hammers.
The use of a hand-held impact tool is known to generate vibrations in the tool, the vibrations then being transferred to the user. Vibrations occurring during the use of hand-held devices, such as chipping hammers, jackhammers, riveters, jackleg drills, grinders, sanders, nail hammers, orbital sanders, chain saws, lawn mowers and edge trimmers, to name but a few, are well known to the legions of users of such devices.
Understandably, it is desirable to reduce the vibrations transferred to the hand during the use of hand-held tools such as impact tools.
This long-felt need has been the object of numerous attempts at vibration reduction in the prior art. For example, thick rubber gloves have been proposed as insulation means for reducing vibrations transferred to the hand. Similarly, thick rubber handles on impact tools have been proposed. However, the thickness required of the rubber component of these prior art devices makes them difficult to hold. Thus, the prior art devices introduce a new problem to the user. If the rubber glove or handle is made of a size to comfortably fit in the hand, then the effectiveness of the device to reduce vibrations may be compromised.
In those prior art devices using a thick rubber, or elastomeric, handle cover, the elastomer tends to harden over time. Thus, as the elastomer ages, the ability of the handle cover to reduce vibrations may diminish.
With respect to hammers, a change in the design of hammers from wood handles to steel or fiber glass handles has occurred. Wood hammer handles inherently offer a limited degree of vibration dampening. But because of the breakage over time of the wood handle, the trend has been towards hammers having steel or fiber glass handles.
Various attempts have been made to reduce vibrations produced by a hammer striking a surface. Hammers have been developed, for example, that have minimal rebound or recoil characteristics. Such hammers are sometimes referred to as xe2x80x9cdead blowxe2x80x9d hammers. In one very early prior art device, when the hammer is struck against a surface, the striking head is forced against a cushion that reportedly absorbs a portion of the shock of impact produced by the strike. Yet another early device included a slug, a charge of round shot, or a charge of powdered material in a chamber immediately behind a striking face of the hammer. This material in the chamber reportedly absorbed some of the forces produced by the hammer strike.
Other prior art devices have resorted to the use of elastic inserts and springs as shock absorbing members. During a strike of the hammer, vibrations are said to be dissipated through the shock-absorbing member. Other prior art devices employ a weight that is designed to move towards the striking portion of the hammerhead when it impacts a surface, thus impacting the striking portion to reduce hammer recoil. Such prior art devices introduce a new problem to the user in that the slidable weight itself tends to recoil, thus, causing undesirable vibration.
It would therefore be an advantage to have a material suitable for use as a handle cover for impact tools and related devices, such that the material reduces vibrations set up in the tool handle during use. It would also be an advantage to have a vibration reducing handle cover for an impact tool, the handle cover having a conventional thickness as compared to prior art handle covers. It would be an even further advantage to have a vibration dampening cover for hammer handles.
In accordance with the principals of the present invention, there is provided a material suitable for use as a handle cover for impact tools and related devices, such that the material reduces and quickly dampens vibrations set up in the tool handle during use.
The present invention also provides: a vibration dampening grip for an impact tool, the vibration dampening grip including: a grip material comprising a cured mixture of an organisol having a Shore A durometer of from about 63 to about 73 and a closed cell organisol foam, the closed cell organisol foam comprising a blowing agent, such that the blowing agent provides no more than about a 37 percent blow as measured in the organisol foam. The grip material is bonded to the impact tool.
Thus, it will be seen that according to principals of the present invention there is provided a vibration reducing grip material. According to one embodiment of the present invention, there is provided a vibration reducing handle cover for an impact tool. According to another embodiment of the present invention, there is provided a vibration reducing handle cover that does not significantly harden over time.